1. Field of the Invention
The present invention relates to a head mounted type display apparatus, and more particularly to a head mounted type display apparatus using a display device and an ocular optical system in a state of being mounted on a head section of the user.
2. Description of the Related Art
To date, various types of head mounted type display apparatus such as a head mounted display have been proposed which extends downwardly from the head section of the user to cover the user's face when mounted. Unlike different portable displays, these types of display apparatus are advantageous in that a picture is observable without the use of the hands.
As one of such head mounted type display apparatus there has been known a binocular display apparatus, such as is disclosed in Japanese Unexamined Patent Publication No. 3-289615, which comprises first and second small-sized display units respectively capable of independently presenting picture displays, first and second optical systems for enlarging each of the displayed pictures on the first and second display units so that the pictures are separately visible with both eyes, a view mechanism for holding the first and second optical systems and the first and second display units and further for separately intercepting the external light at least between the first display unit and the first optical system and between the second display unit and the second optical system, a carrying body mounted and used on the head section or the like of the user so that the first optical system held by the view mechanism comes in the right-eye's field of view while the second optical system held thereby enters the left-eye's field of view, and a control means for taking charge of the display control of the first and second display units.
In addition, Japanese Unexamined Patent Publication No. 1-133479 has disclosed another head mounted type display apparatus designed as a visual system in which a light-emitting section of a television is located to be in the dead angle of both the eyes of the user and the television screen taking the light-emitted condition just reaches both the eyes through a concave mirror and which is arranged to be detachably mounted on the head section.
On the other hand, headphones have generally been employed as a sound outputting means applicable to the aforesaid head mounted type display apparatus. These headphones are classified into a hermetic headphone of the type of shutting out the environmental noises to allow the outputted sound to be clearly audible, an open headphone of the type whereby both the environmental voices and outputted sound are audible and an inserted headphone of the type of achieving the reduction in weight and size to be insertable into the ears.
Moreover, as a sound inputting means applicable to the head mounted type display apparatus, there have been used a common microphone such as an air conduction type microphone, i.e., an electret.diamond.capacitor microphone, the employment of which is made such that, for example, a segment flexible cord section is formed to extend from a supporting section of the head mounted type display apparatus and the aforesaid microphone is attached to its tip portion to approach the mouth of the user. In the case of using the foregoing head mounted type display apparatus as an information processing terminal, if a sound inputting means is provided and used as an inputting means to the information processing terminal, the inputting means such as a keyboard becomes unnecessary, which improves its portability.
However, in the case of the above-described prior head mounted type display apparatus, when receiving, for instance, an electronic mail in the middle of the mounting work, serious troubles can occur depending upon the kind of work because of informing the user of the reception through a sound or a picture. In addition, if using a display or a low voice which does not affect the work, there is a possibility that the user does not notice the reception news.
Moreover, in cases where the hermetic headphone is employed as the sound outputting means applicable to the aforesaid head mounted type display apparatus, the apparatus becomes larger in size and weight. On the other hand, in the case of using the open headphone, it is necessary that the headphone mounting position is adjusted so that the headphone position matches the ear positions, and hence an adjusting mechanism is required, which creates a problem in that the apparatus increases in weight and the adjusting work is troublesome. Further, in the case of employing the inserted headphone, it becomes difficult that the user inserts the inserted headphone into his ear after the mounting of the head mounted type display apparatus, and the cord plugged into the inserted headphone hangs close to the ear of the user to be in the way.
Still further, in the case of the prior sound inputting means applicable to the aforesaid head mounted type display apparatus, an extending section is required in order to bring the microphone close to the mouth of the user, which leads to the increase in weight of the apparatus.